Caramelized onions add a whole lot of flavor with very few ingredients and even less effort, so long as you know the secrets. Here’s how to do it.

Chopped onion is the foundation to oh-so many recipes. But as everyone knows, raw and sometimes even sautéed onions can be intense or overpowering.

But when sliced onions are cooked low and slow in a bit of butter and oil, they become savory bites of sweet candy that are nearly jam-like, transforming everything from burgers to pizza to pastas, and definitely chips in dips, with their deep, rich, and nutty sweetness.

Don’t even get me started on soup. French Onion Soup without caramelized onions would simply be tepid broth, and who’s craving that?

Ingredients for Easy Caramelized Onions

It’s not necessarily the ingredients that make caramelized onions a success, it’s time and patience. Low and slow is the name of this caramelized onion game. Like all simple recipes, the fewer the ingredients, the more important it is to do it right because there’s no cover to mask mistakes.

I typically use yellow onions for this recipe, but sweet Maui onions and even red onions each work well too. Slice the onions in half from stem to stem, then slice into half moons. You’ll have a whole lot of onion at the start, but as it cooks, those onions melt down considerably.

I use a cast iron skillet or a heavy bottom skillet so the onions deepen and darken and create little bits of frond (the buttery sugar remnants) on the bottom of the pan that are periodically stirred into the whole goodness.

Oil, either vegetable, olive, or canola, is added with butter, melting together to create a higher smoke point so the onions slowly brown but don’t burn.

Kosher salt is always my go-to and helps draw out the moisture as the onions so they soften as they cook. I add the salt at the beginning of the process.

I add fresh thyme to my onions because I love the herbal flavor it imparts. It’s really the perfect partner for the caramelized flavor.

Mom, Are We There Yet? How Long Does It Take to Cook Caramelized Onions?

You want the onions to cook slowly to release their sugars and caramelize, stirring just every so often so the onions become bronzed and jammy. Sure this process takes time—at least one hour over medium low heat—but this isn’t a dish you have to sit and babysit the entire time. In fact allowing the onions to gel together without stirring deepens their flavor.

If the onions look like they’re on the verge of burning or get dry, add a little water or stock to loosen them and rehydrate. Some recipes suggest adding a splash of vinegar to brighten the process, and sometimes I do and sometimes I don’t. It’s your call.

The onions are done once they’ve reached their bronzed beauty look. I feel they’re a success when I have deep and dark strands entwined with lighter plump strands holding all that onion essence. Once you’ve made these a few times you’ll discover your favorite way too.

Short On Time? How to Caramelize Onions Quickly

If your craving doesn’t jive with the hands on the clock and those onions need to be done in a hurry, take this short cut route. They’re not quite as good as the low and slow method, but they’ll do in a pinch.

If you make this recipe, please let me know! Bookmark this recipe and leave a comment below, or take a photo and tag me on Instagram with #foodiecrusheats.

Caramelized onions take time for the flavor to develop but not a whole lot of hand-holding. Allow the onions to cook undisturbed in between stirring times for the caramelization to happen naturally.

Serves: 1¾ to 2 cups

Ingredients

2 tablespoons butter

1 tablespoon canola oil

3 large yellow onions, peeled, halved and thinly sliced

1 teaspoon kosher salt

3 sprigs fresh thyme, leaves only

1 tablespoon white balsamic vinegar (optional)

Instructions

Melt the butter with the canola oil in a large cast iron or heavy bottomed skillet over medium high heat. Add the onions and sprinkle with the kosher salt and fresh thyme leaves. Cook the onions for 5 minutes or until they start to soften, stirring so they don't crisp or brown in spots. Reduce the heat to medium low, cover with a lid, and continue to cook, stirring the onions every 10-15 minutes or so. The onions will reduce and become more golden and jammy as they cook, giving off a rich nutty aroma. If the onions look like they're beginning to burn or crisp, stir in a splash of water or broth and scrape the caramelized fond from the bottom of the pan for the onions to absorb. Add the vinegar if desired in the last 10 minutes of cooking. Continue to cook up to 1 hour or so for a deep, rich caramelized flavor. Serve immediately or refrigerate for up to one week.

Agreed Sally! Low and slow is the way to go, otherwise the flavor and color simply don’t deepen for that lush candy sweetness. I haven’t tried them in the slow cooker but it sounds like your plan of popping them outdoors is a good one to remember. Thanks for the tip!

Thanks for the comprehensive explanation for how to do this. After learning by “winging it” many years ago, I’ve made this a number of times, usually to go with roast beef or a steak, using Vidalia onions. I also grind up some fennel and anise seeds to sprinkle into the onions while they’re cooking, but will have to try them with fresh thyme. Depending on what they’re to accompany, I will use a bit of beef or chicken broth instead of or in addition to water.

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